Although humans have used chemicals to control pests since before 2500 BC, it is only relatively recently that chemical control has been widely used. Early pesticides included hellebore to control body lice, nicotine to control aphids, and pyrethrum to control insects. In 1939 DDT was discovered to be a very effective insecticide and quickly became the most widely used pesticide in the world. In the 1940's manufacturers began to produce large amounts of synthetic pesticides and their use became widespread. Further developments of pesticides followed, and with their relatively low cost, ease of use and effectiveness, they became the primary means of pest control.
Although there are many benefits to the use of pest control materials and pesticides, there are also drawbacks, such as potential toxicity to humans and other animals, as well as persistence and accumulation of toxic materials in the environment. There is a growing requirement for more natural pest control actives that are safer, do not persist in, and are friendlier to the environment. There is also a need for improved formulation such that the odour and/or stability of the composition is improved, more consistent pest control is obtained, and/or the effectiveness of pest control is increased. This can enable lower concentrations of actives to be used, with a resultant reduced detrimental impact on the environment.